The invention relates to cameras and photography and more particularly relates to a binocularly viewable holographic viewfinder and camera.
Eyepiece-viewfinders of cameras present some difficulties for new photographers and persons wearing a facial encumbrance, such as a pair of eyeglasses, a diving mask, a costume mask, or, even a hat. A partial solution is increasing the size of the viewfinder eyepiece. This helps, but a relatively small increase in viewfinder eyepiece size is accompanied by a relatively large increase in camera size and weight. An alternative approach is described in U.S. Pat. No. 5,500,702 and U.S. Patent Application Publication No. US2001/0,016,084 A1. These publications disclose image capture devices that project marker beams toward a subject. Holographic optical elements are used as diffraction optical elements in the production of the marking beams. This approach is complex and is unsuitable for situations that present a risk of a marker beam appearing in a captured image. Such a situation occurs when many photographers shoot the same scene or overlapping scenes at the same time.
U.S. Pat. No. 6,125,239 discloses a camera viewfinder, which incorporates a holographic optical element that acts as a diffraction optical element. The holographic optical clement is used to redirect light from an information display through an eyepiece to the photographer.
U.S. Pat. No. 5,978,607 discloses a camera having a viewfinder, in which a holographic element is interposed between the lenses of the viewfinder. Information and images can be projected onto the holographic element by a raster scanned light source. The holographic element can be permanently provided with framing radicals by etching or painting techniques or the like. Images of radicals can also be projected onto the holographic element by the scanned and modulated beam of the optical system.
The last two patents have the shortcoming that the user has to look through the eyepiece with one eye to see the viewfinder image. The earlier two patent publications, don""t require looking through the viewfinder, but interfere with the scene.
It would thus be desirable to provide a camera and viewfinder in which marker beams are not projected toward a scene to be captured and the scene to be captured is visibly delimited and can easily be perceived with both eyes.
The invention is defined by the claims. The invention, in broader aspects, provides a camera and viewfinder. The camera has a body and a taking lens mounted to the body. The taking lens defines a subject field. A viewing window is joined to the body. The viewing window is transmissive of a light image of the subject field. The viewing window bears a holographic image of a reticle. A light source faces the viewing window and illuminates the holographic image. The reticle produced can be binocularly viewable, that is, viewable by the photographer with both eyes while the photographer looks through the viewing window to compose a scene image for picture taking.
It is an advantageous effect of the invention that a camera and viewfinder are provided in which marker beams are not projected toward a scene to be captured and the scene to be captured is visibly delimited and can easily be perceived with both eyes.